scholarly journals A Novel Factor Isolated from Actinobacillus actinomycetemcomitans Stimulates Mouse B Cells and Human Peripheral Blood Mononuclear Cells

2000 ◽  
Vol 68 (9) ◽  
pp. 5132-5138 ◽  
Author(s):  
Soo-Jin Jeong ◽  
Sung-Tae Yee ◽  
Wol-Soon Jo ◽  
Seong-Ho Yu ◽  
Sang-Hwa Lee ◽  
...  

ABSTRACT A novel immunostimulating factor (ISTF) of Actinobacillus actinomycetemcomitans ATCC 29522 was isolated and characterized as inducing proliferation of mouse B cells and human peripheral blood mononuclear cells. This factor was isolated from the bacterial culture medium and purified by size exclusion chromatography, dye-ligand affinity chromatography, immunoaffinity chromatography using monoclonal antibodies, and preparative electrophoresis. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the purified ISTF migrated as a single band corresponding to a molecular mass of 13 kDa. ISTF was a proteinaceous material distinct from lipopolysaccharide; it directly induced the proliferation of B lymphocytes but had no effect on the proliferation of T lymphocytes, even in the presence of antigen-presenting cells. A B-lymphocyte-mitogenic activity of ISTF was also shown by flow cytometric analysis of responding cell subpopulations. Immunoblot analysis revealed that ISTF was a component of the outer membranes of bacteria, could exist as a soluble form, and was released by growing and/or lysed bacteria. These results suggest that ISTF produced byA. actinomycetemcomitans may play an important role in immunopathologic changes associated with A. actinomycetemcomitans infections.

Blood ◽  
1989 ◽  
Vol 74 (4) ◽  
pp. 1348-1354 ◽  
Author(s):  
HG Klingemann ◽  
S Dedhar

Abstract The receptors for fibronectin (FN-R) and vitronectin (VN-R) belong to a family of integral membrane glycoproteins known to be involved in cell- extracellular matrix and cell-cell interactions named integrins (FN-R = beta 1 integrin and VN-R = beta 3 integrin). Adhesion studies using FN- coated plastic dishes and highly purified subpopulations of peripheral blood mononuclear cells (PBMCs) showed a strong binding of monocytes and T lymphocytes to FN but virtually no binding of B cells to FN. Binding of monocytes and T cells to FN could be partially inhibited by a hexapeptide (GRGDSP) containing the adhesive peptide sequence Arg-Gly- Asp (RGD) as well as by an anti-FN-R antibody. The distribution of beta 1 and beta 3 integrin complexes on PBMCs was characterized by immunoprecipitation of detergent extracts of 125I-labeled cells using polyclonal antibodies against these two receptors. Two surface polypeptides corresponding to the alpha and beta chains of FN-R and VN- R were found on all three cell types. To characterize these receptors further, monoclonal antibodies (MoAbs) against the very late antigens (VLAs) 1, 3, and 5 were used for immunoprecipitation studies. Monocytes and T cells reacted with VLA 5 that was previously identified as the human FN receptor, whereas no labeling with anti-VLA 5 could be shown for B cells. When cell populations were cultured in 10% human serum for 24 hours, an increase in beta 1-integrin+ monocytes and T cells was observed. The number of beta 3-integrin+ cells remained essentially unchanged. The presence of beta 1 and beta 3 integrins on monocytes as well as on T and B lymphocytes may be of significance in the ability of these cells to interact with each other and participate in hematopoiesis and certain immune reactions.


Blood ◽  
1989 ◽  
Vol 74 (4) ◽  
pp. 1348-1354
Author(s):  
HG Klingemann ◽  
S Dedhar

The receptors for fibronectin (FN-R) and vitronectin (VN-R) belong to a family of integral membrane glycoproteins known to be involved in cell- extracellular matrix and cell-cell interactions named integrins (FN-R = beta 1 integrin and VN-R = beta 3 integrin). Adhesion studies using FN- coated plastic dishes and highly purified subpopulations of peripheral blood mononuclear cells (PBMCs) showed a strong binding of monocytes and T lymphocytes to FN but virtually no binding of B cells to FN. Binding of monocytes and T cells to FN could be partially inhibited by a hexapeptide (GRGDSP) containing the adhesive peptide sequence Arg-Gly- Asp (RGD) as well as by an anti-FN-R antibody. The distribution of beta 1 and beta 3 integrin complexes on PBMCs was characterized by immunoprecipitation of detergent extracts of 125I-labeled cells using polyclonal antibodies against these two receptors. Two surface polypeptides corresponding to the alpha and beta chains of FN-R and VN- R were found on all three cell types. To characterize these receptors further, monoclonal antibodies (MoAbs) against the very late antigens (VLAs) 1, 3, and 5 were used for immunoprecipitation studies. Monocytes and T cells reacted with VLA 5 that was previously identified as the human FN receptor, whereas no labeling with anti-VLA 5 could be shown for B cells. When cell populations were cultured in 10% human serum for 24 hours, an increase in beta 1-integrin+ monocytes and T cells was observed. The number of beta 3-integrin+ cells remained essentially unchanged. The presence of beta 1 and beta 3 integrins on monocytes as well as on T and B lymphocytes may be of significance in the ability of these cells to interact with each other and participate in hematopoiesis and certain immune reactions.


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